P2Y12 Inhibitor Utilization for Acute Coronary Syndrome in the Elderly: A Provincial Analysis From 2008 to 2018

Background Guidelines recommend acetylsalicylic acid (ASA) and ticagrelor following acute coronary syndrome (ACS), but appropriate prescription practices lag. We analyzed the impact of government medication approval, national guideline updates, and publicly funded drug coverage plans on P2Y12 inhibitor utilization.Methods Accessing provincial databases, we obtained data for elderly ACS patients in Ontario, Canada between 2008 and 2018. Using an interrupted-time series, we evaluated types of P2Y12 inhibitors prescribed at discharge, and changes to their utilization following ticagrelor’s national approval by Health Canada, national antiplatelet therapy guidelines (by the Canadian Cardiovascular Society (CCS)), and ticagrelor's coverage by a publicly funded medication plan.Results We included 114,142 patients (49.4%-PCI and 7.7%-CABG). Proportion of PCI patients utilizing P2Y12 inhibitors increased from 73.4% to 86.9% (p<0.001) and 11.4% to 46.5% (p<0.001) for CABG patients. Among PCI patients, clopidogrel utilization declined monthly after 2010 national guidelines were published (0.7%; p<0.0001) and within the first month after ticagrelor’s national approval by Health Canada (5.3%; p=0.03). Among PCI patients, ticagrelor utilization increased within the first month (24.5%; p<0.0001) and continued increasing monthly (0.4%; p<0.0001) after its coverage by a publicly funded medication plan. Among CABG patients, ticagrelor’s coverage was associated with a monthly increase in its utilization (0.2%; p<0.0001). Among PCI patients, clopidogrel utilization declined within the first month (6.1%; p=0.003) and ticagrelor utilization increased monthly (0.3%; p=0.05) after 2012 CCS guidelines.Conclusion National guideline updates and drug coverage by a publicly funded medication plan significantly improved P2Y12 inhibitor utilization. Barriers to appropriate antiplatelet therapy in the surgical population must be explored.